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authorAndreas Schwab <schwab@suse.de>2009-01-27 21:45:57 +0100
committerIngo Molnar <mingo@elte.hu>2009-01-30 23:55:25 +0100
commit7fc49f19813030f2e15ad2ccec5cb701f7f4a3ec (patch)
treeb4e52b975777e18151811019541e24f0a6f2bfc8
parent618b2c8db24522ae273d8299c6a936ea13793c4d (diff)
x86 setup: fix asm constraints in vesa_store_edid
Impact: fix potential miscompile (currently believed non-manifest) As the comment explains, the VBE DDC call can clobber any register. Tell the compiler about that fact. Signed-off-by: Andreas Schwab <schwab@suse.de> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--arch/x86/boot/video-vesa.c11
1 files changed, 5 insertions, 6 deletions
diff --git a/arch/x86/boot/video-vesa.c b/arch/x86/boot/video-vesa.c
index 75115849af3..4a58c8ce3f6 100644
--- a/arch/x86/boot/video-vesa.c
+++ b/arch/x86/boot/video-vesa.c
@@ -269,9 +269,8 @@ void vesa_store_edid(void)
we genuinely have to assume all registers are destroyed here. */
asm("pushw %%es; movw %2,%%es; "INT10"; popw %%es"
- : "+a" (ax), "+b" (bx)
- : "c" (cx), "D" (di)
- : "esi");
+ : "+a" (ax), "+b" (bx), "+c" (cx), "+D" (di)
+ : : "esi", "edx");
if (ax != 0x004f)
return; /* No EDID */
@@ -285,9 +284,9 @@ void vesa_store_edid(void)
dx = 0; /* EDID block number */
di =(size_t) &boot_params.edid_info; /* (ES:)Pointer to block */
asm(INT10
- : "+a" (ax), "+b" (bx), "+d" (dx), "=m" (boot_params.edid_info)
- : "c" (cx), "D" (di)
- : "esi");
+ : "+a" (ax), "+b" (bx), "+d" (dx), "=m" (boot_params.edid_info),
+ "+c" (cx), "+D" (di)
+ : : "esi");
#endif /* CONFIG_FIRMWARE_EDID */
}